Toy transformer



Sept. 18,1928. 1,684,746

B. H. SMITH ET AL TOY TRANSFORMER Filed March 31, 1926 WITNESSES:INVENTORS B ff. Smith, M gfilzerfon, and

ml reibach by WWCIQA Patented Sept. 18, 1928.

UNITED STATES BENJAMIN E. SMITH, F SWISSVALE, AND ALFRED L.

ATHERTON AND EMIL H.

GREIBACH, OF PITTSBURGH, PENNSYLVANIA.

TOY TRANSFORMER.

Application filed March 31, 1926. Serial No. 98,636.

Our invention relates to transformers and particularly to toytransformers.

One object of our invention is to provide transformer that shall becapable of a to 6 prodiicing a variable voltage without the use of tapsor of multiple windings.

Another object of our invention is to provide a toy transformer thatshall be capable of producing any variation in voltage between certainlimits.

Another object of our invention is to provide a transformer that shallhave means for opening the circuit of its secondary winding underpredetermined conditions. Another object of our invention is to providea toy transformer that shall have minimum copper and iron for a givencapacity.

Another object of our invention is to provide a toy transformer thatshall have means for increasing its impedance when its secondary windingis short-circuited to preclude overheating and burning of the windin s.

another object of our invention is to provide a toy transformer, of theabove indicated character, that shall not overheat upon short-circuitingits secondary Winding irrespective of the relative position of thewindings.

A further object of our invention is to provide a transformer, of theabove indicated character, that shall be inexpensive to construct andthat shall be simple and effective in its operation,

In practising our invention, we provide a magnetizable core memberhaving an inner and two outer legs with different width air gapstherebetween. A stationary winding is disposed around the inner leg inthe 40 larger air gaps while a movable winding is adapted to have asliding fit around the inner leg to permit it to be disposed within thestationary winding and to be laterally moved therefrom. A handle isprovided for actuating the movable winding and the circuit of themovable winding is interrupted when it is moved to its limit of travelaway from the stationary winding. With this arrangement, a great rangeof voltages may be obtained without the use of taps and this furtheradapts our device for controlling toy trains and toy electric motors asmovement of the movable windin also serves as the movable member of aswitch for controll g the circuit of the same. windings are so arrangedand proportioned that when the secondary winding is shortcircuited, theyare so mutually repelled as to move one with respect to the other toincrease the impedance in the circuit and, thus, preclude overheatingunder such conditions.

In the accompanying drawings, Fig. 1 is a side view, partially insection of a transformer embodying our invention.

Fig. 2 is a front view, artially in plan and partially in section, 0 thetransformer sh%wn in Fig. 1. e

1 3 is a view taken alon the line III III o f Fig. 2. g

Fig. 4 is a view taken along the line IV- IV of Fig. 2 and;

Fig. 5 is a detail view of a modified form of operating mechanismembodying our invention.

Our invention comprises, in general, a base member 6,- a casing 7, acore member 8, a stationary winding 9, a movable winding 10 and anactuating member 11.

The core member 8 is constructed of laminations that are so punched thatthe completed core has two outer legs12 and 13 and an inner leg 14.Relatively wide air gaps 15 are formed between the leg 14 and the legs12 and 13 at one end of the member 8, while relatively narrow air gaps16 are formed between the leg 14 and the legs 12 and 13 at the other endof the member. 'A conducting lamination 17 of brass, similar to themagnetizable laminations of the core, is disposed at one side of thecore member 8 and it is insulated from the core member 8 by a sheet ofinsulating material 18. Similarly, a conducting lamination 19 isdisposed on the other side of the core member 8 and 95 is insulatedtherefrom by an insulating sheet 20. The lamination 19, however, is cutaway between the points 21 and 22 for purposes hereinafter set forth.

The stationary or primary winding 9 is If") disposed in the air gap 15and is of sufficient internal diameter to permit the winding 10 to beslidable therein. The winding 10 is disposed around and is slidablealong the leg 14 and constitutes the secondary winding 105 of thetransformer. The winding 10 is provided with conducting strips 23 and 24along opposite sides of the internal surface which strips engage theconducting laminations l7 and 19 respectively. Thus, when 11*Furthermore, the

the winding 10 is moved to such position that the strip 24': disengagesthe lamination 19 between the points 21 and 22, the circuit of thewinding 10 is interrupted and the device (not shown) that is connectedto the terminals 25 and 26 is de-energized.

A number of magnetizable washer shaped members 27 are disposed aroundthe leg 14 adjacent the upper end of the winding 10 and are movabletherewith. The magnetizable members 27 are split at 28 to preventcirculation of current therein. The member 11 has a knob 29 on the outerend thereof and its inner end is connected to the movable winding 10 toactuate the same.

' the same to a lamp or other suitablesocket.

In Fig. 5, we have shown a lever arm 31 that is pivoted on the casing 7for actuating the movable winding 10 should it be desired to use a leverinstead of a rod as shown in Fig. 1.

When the winding 10 is disposed within the winding 9, the maximumVoltage is impressed upon the winding 10 and, consequently, this voltageis available at the terminals 25 and 26 which are secured, respectively,to the laminations 17 and 19. The washers 27 have substantially noeflect on the reluctance of the magnetic circuit in this position andthe interlinkage of'flux is a maximum. However, when the windin 10 ismoved longitudinally out of the windin 9, the washers 27 act as magneticshunts to shunt the flux away from the winding 10 to thus permit ofobtaining relatively low voltage on the winding 10 without moving thesame a relatively great distance from the winding 9. It will be notedthat this leakage is also accentuated by reason of the fact that thereluctance of the magnetic circuit is a minimum because of the narrowair gap 16. \Vith this arrangement, the amount of iron in the coremember 8 is a minimum because the length of the same is relativelyshort. However, if the travel of the winding 10 is increased, the washermembers 27 may be omitted.

Whenit is desired to open the circuit of the winding 10, the same ismoved to cause the strip 24 to disengage the conducting lamination 19.Similarly, when this strip 24 again engages the lamination 19, thecircuit is completed. It will be observed that the single handle 11controls the movement of the winding 10 to obtain a variable voltage andto control the continuity of the circuit, thus particularly fitting thesame for use with toy electric trains and other toy electric motors.

When the windings 9 and 10 are in the position of maximum effectiveness,it will be observed that should the winding 10 be short-circuitedacoidently as frequently occurs in toy track systems, the windings willrepel each other to move the winding 10 out of the winding 9 and soincrease the impedance of the circuit that the windings will notoverheat under this condition. Also the impedance of the circuit issuch, when the winding 10 is in the position shown in Fig. 2, thatshould it be short-circuited, no overheating will result.

Many changes may be made in our invention without departing from thespirit and scope of the invention as set forth in the appended claims. 5

We claim as our invention:

1. A toy transformer comprising a magnetizable member having a centralleg and two side legs, a relatively wide air gap between one portion ofthe legs and a narrow air gap between another portion of the legs, astationary windin in the wide air gap, a movable winding adapted tosurround the central leg and to be slidably mounted thereon, and amagnetizable shunt member mounted on the movable winding andsubstantially closing the narrow air gap when the movable winding isremoved from the stationary winding.

2. A toy transformer comprising a magnetizable member having a centralleg and two side legs, a relatively wide air gap between one portion ofthe legs and a narrow air gap between another portion of the legs, astationary winding in the wide air gap,

a movable winding adapted to surround the central leg and to be slidablymounted there-' on, and magnetizable means on the movable winding andmovable therewith for shunting the flux across the narrow air gapbetween the windings when the movable winding is removed from thestationary winding.

3. A toy transformer comprising a magnetizable member having a centralleg and two side legs with different width air gaps therebetween, tworelatively movable windings on said central leg, means for actuating oneof the windings, means for shunting the flux from one of the windings,and contact plates in the circuit of one of said windings,- said contactplates being disposed on the central leg of the magnetizable member andbeing of such length that the circuit of said winding is interruptedwhen the flux-shunting means is efiective.

4. A toy transformer comprising a mag-. netizable member having acentral leg and two side legs with different width air gs. stherebetween, two relatively movable win ings, means for actuating oneof the windings, and contact plates in the circuit of saidlast-mentioned movable winding, said contact plates being disposed onthe magnetizable member and being of such length that the circuit ofsaid winding is interru ted when the winding is" actuated to a preetermined pos tion.

5. A transformer comprising a magnetizable core member, relativelymovable windings thereon, a stationary contact element in the circuit ofone of said windings disposed on said core member, and a cooperatingcontact element secured to said one of said windings and arranged tohave, sliding engagement with the stationary contact element, saidcontact elements being so arranged that the circuit of said winding isinterrupted thereby in one relative position of the wind.

ings.

I 6. A transformer'comprising a magnetizable core member having arectilinear portion, relatively movable windings on said rectilinearportion of the'core member, a flat contact plate secured to saidrectilinear portion of the core member, and a contact member secured toone ofsaid windings and adapted to engage said contact plate, saidcontact plate being of such length that predetermined movement of saidone of said windings effects disengagement of the contact elements tointerrupt the circuit of the windg A transformer comprising amagnetizable core member having a central leg and two outer legs, twotelescoping relatively movable windings surrounding the central leg ofthe core member, said central leg being of sufficient length to permitone of said windings to be separated from the other, and means forcontrolling the leakage flux in the transformer which is effective whenthe windings are separated, said means including a magn'etizablering-shaped member surrounding the central leg of the core member andsecured to one of said windings.

8. A transformer comprising a magnetizable core member having a centralleg and two outer legs, the configuration of said legs being such as toprovide a larger air gap at one end of the core member than at theother, a stationary winding surrounding said central leg of the coremember in the larger air gap, a movable winding adapted to lie wholly-Within said stationary winding in .one position thereof and a infrictional engagement with and in the cirterminal connection. r

10. A transformer comprising a magnetizable core member having spacedegs forming a wide air gap at one portion of the legs and a narrow air,gap at another portion thereof, a stationary winding in the wide airgap, a second winding movable with recuitof the movable winding toprovide a mg in such relation as to bridge the'narrowspect to thefirst-mentioned winding and a magnetizable shunt member mounted on themovable winding and substantially closing the narrow air gap when themovable winding is removed from the stationary winding.

11. A transformer comprising a magnetizable core member having spacedlegs, two telescoping relatively movable windings on one leg of saidcore member, said leg being of sufiicient length to permit one of saidwindings to be separated from the other, and means for controlling theleakage flux in the transformer which is effective y when the windingsare separated, said means including a magnetizable member secured to oneof said windings and substantially bridging the legs of the core memberwhen the windings are separated.

In testimony whereof, we have hereunto subscribed our names this 26thday of March, 1926.

BENJAMIN H. SMITH. ALFRED L. ATHERTON. EMIL H. GREIBACH.

